1. Field of the Invention
The invention relates to a device for axially connecting an external pipe section to a coaxial peg or internal pipe section that engages in the external pipe section, in particular for connecting the drain connecting piece of an injector for injecting fuel into internal combustion engines to a fuel return connector.
2. Description of the Prior Art
In injectors, in particular so-called common rail injectors, the fuel return is usually connected to a so-called outlet fitting. In this case, a return plug provided with an O-ring is inserted into the inner bore of the outlet fitting. The O-ring seals the connection from the outside environment. In order to prevent an unwanted detachment of the return plug, it is known to fasten the return plug above the O-ring by means of a holding clip. The holding clip is a spring wire bent into a special shape, which is guided by means of two opposing slots milled into the outlet fitting and reaches far enough into the inner bore that the return plug is fastened to a diametrical step and is prevented from moving out of the return bore.
A connection of the injector outlet fitting/return plug according to the above-mentioned prior art is the subject of EP 0 886 065 B1.
During the operation of the injectors in question, powerful vibrational loads occur in the region of the outlet fitting/return plug connection, which can cause the holding clip to execute rapid movements inside the space provided for it. The high frequency impacts of the holding clip against the boundary surfaces of the holding slots in the outlet fitting causes wear on these surfaces. In the worst-case scenario, the wear can result in the destruction of the outlet fitting and the loss of the holding function of the clip.
In order to avoid the above-mentioned disadvantages, a clasped holding clip has been developed, which is wedged into the two holding slots of the outlet fitting so that the holding clip is no longer able to execute any appreciable movement inside the outlet fitting, even in the presence of a powerful vibrational movement. However, this design also turns out to be disadvantageous in that the required clasping of the ends of the holding clip is a relatively imprecise process that is also complex and therefore entails additional costs.
The object of the invention is to assure a play-free connection of the external pipe section, e.g. the outlet fitting of an injector, and the inner pin or pipe section, e.g. the return plug of an injector, without requiring a time-consuming and/or imprecise (plastic) deformation of the holding clip.